To evaluate and monitor modern communication systems, the digitally modulated high-frequency signals used in this context must be recorded using measurement technology. Digitally modulated high-frequency signals of this kind are described by the I/Q configuration diagram. It is already known, for example, from DE 195 47 896 A1, that the configuration diagram for relatively high-order digital modulations of this kind, such as 64 QAM, can be presented to the observer in a direct graphic manner on a screen.
It is also already known, that the I/Q components measured in temporal succession in the I/Q-demodulator of a receiver can be represented graphically on screen either separately or optionally also superimposed simultaneously in such a manner that the spacing of the value clouds representing the individual symbols in the configuration diagram appears on screen as a so-called “eye-diagram.” The so-called “eye-opening” displayed in this manner provides a measure for the quality of the digital modulation and the signal transmission.
One disadvantage of these known methods of representation is that they fail to provide adequate information about the temporal course of any interference which may be present, for example, any periodically-occurring interfering pulses. Moreover, with the known method of representation, only a fraction of the I/Q data actually present, which are registered within a short time window, are displayed and presented on screen. A large number of measured values are not registered at all, and the representation therefore contains considerable gaps.